Ultrasonic surgical instrument and method for manufacturing same

ABSTRACT

An ultrasonic surgical instrument comprises a cylindrical shaft and a blade at a distal or free end of the shaft, the blade being unitary and continuous with the shaft, without an intervening joint. The shaft has a longitudinal axis and the blade includes a flat or planar blade body with a proximal end eccentrically disposed relative to the shaft axis. Thus, the blade body or at least a proximal end portion thereof is disposed eccentrically relative to the shaft. The blade in its entirely may be inclined relative to the shaft axis or extend parallel thereto.

BACKGROUND OF THE INVENTION

This invention relates to an ultrasonic surgical tool or instrument.This invention also relates to a method for manufacturing the tool orinstrument.

U.S. Pat. No. 6,379,371 discloses an ultrasonic surgical blade,particularly for cutting bone tissue, which has a blade body with asmooth continuous cutting edge and a shank connected at one end to theblade body and operatively connectable at an opposite end to a source ofultrasonic vibrations. The shank is provided with an axially extendingbore for the conveyance of cooling fluid to the cutting edge, while theblade body is provided with an axially extending through-slotcommunicating at one end with the bore. The blade body is preferablyprovided at an end opposite the shank with a recess communicating, withthe bore for distributing fluid from the slot towards the cutting edge.The recess preferably has a configuration which parallels at least aportion of the cutting edge. Where the cutting edge is circular and theblade body has a planar surface between the fluid distribution guidesurface and the cutting edge, for instance, the recess has a fluiddistribution surface inclined with respect to the planar blade surfaceand extending along a circular arc.

In the manufacture of such a bone-cutting instrument, the blade body isgenerated separately and then affixed to the end of a tubular shaft.Thus there is a joint between the instrument shaft or horn and theblade.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide an improvedultrasonic instrument particularly a bone-cutting blade.

Another object of the present invention is to provide such a tool orinstrument wherein joints are reduced if not eliminated.

A further object of the present invention is to provide such a tool orinstrument wherein manufacture is facilitated.

It is a concomitant object of the present invention to provide such atool or instrument which may be produced at less expense than existinginstruments.

Yet another object of the present invention is to provide a method formanufacturing an ultrasonic bone cutting instrument or tool.

These and other objects of the invention will be apparent to thoseskilled in the art from the drawings and descriptions hereof. Althougheach object is attained by at least one embodiment of the invention, noembodiment need necessarily meet every object.

SUMMARY OF THE INVENTION

An ultrasonic surgical instrument in accordance with the presentinvention comprises a cylindrical shaft and a blade at a distal or freeend of the shaft, the blade being unitary and continuous with the shaft,without an intervening joint. As discussed hereinafter, the manufactureof this instrument entails machining a distal end of a tool blank andparticularly a distal end portion of a shaft thereof.

The surgical instrument typically further comprises a radially ortransversely enlarged proximal end portion at a proximal end of theshaft opposite the blade. The enlarged proximal end portion isconfigured for attachment to an electromechanical transducer device suchas a piezo-electric stack housed inside an instrument hand piece.

Pursuant to a further feature of the present invention, the shaft has alongitudinal axis and the blade includes a flat or planar blade bodywith a proximal end eccentrically disposed relative to the shaft axis.Thus, the blade body or at least a proximal end portion thereof isdisposed eccentrically relative to the shaft.

Pursuant to another feature of the present invention, the blade body hasat least one edge or peripheral surface that is a cylindrical sectioncontinuous and coaxial with a cylindrical outer surface of the shaft.

In one embodiment of the present invention, the blade body extends in aplane parallel to the shaft axis.

The shaft has an end face contiguous with the proximal end of the bladebody and also has a channel or bore with an outlet in the end face.

According to another aspect of the present invention, where the bladebody has a major lateral surface facing the axis, the blade body isprovided in the major lateral surface with a groove continuous with thechannel or bore at the outlet thereof. The groove may extend the lengthof the blade body to a distal end of the blade body. Alternatively,where the blade body is provided with a through slot or hole, the grooveextends from the outlet of the shaft channel or bore to a proximal sideof the through slot or hole.

The blade body may be provided at a distal end, opposite the shaft, witha beveled surface inclined with respect to the axis. Alternatively oradditionally, the blade body may be formed with an arcuate distal tip,where the distal tip has a circular or cylindrical surface with an axisoriented perpendicular to the shaft axis.

In a second embodiment of the present invention, the blade body extendsat an angle with respect to the axis and intersecting the shaft axis.Where the shaft has an end face contiguous with the proximal end of theblade body and additionally has a channel or bore with an outlet in theend face, the blade body has a planar first major lateral surface and aplanar second major lateral surface facing oppositely to one another.

Pursuant to another feature of the present invention, the blade body isprovided in the first major lateral surface with a groove continuouswith the channel or bore at the outlet. The blade body may be furtherprovided with a through hole at an end of the groove opposite the endface and the outlet, the groove extending from the outlet to the throughhole. The second major lateral surface may formed with an additionalgroove communicating with the through hole. The additional groove ispreferably tapered from a wide end at the through hole and a closednarrow end at the second major lateral surface. The second major lateralsurface may take the form of an annular oval surface with an oval centeredge formed by the through hole and the additional groove.

The blade body of this second embodiment may have an endless peripheralor perimetric surface continuous with a cylindrical outer surface of theshaft, the peripheral or perimetric surface being a cylindrical sectioncoaxial with the outer surface of the shaft.

The present invention is also directed to a method for manufacturing aunitary ultrasonic surgical instrument having a shaft portion and ablade portion at a distal of free end of the shaft, the blade beingunitary and continuous with the shaft, without an intervening joint. Themethod comprises providing a tool blank including an enlarged connectorportion at one end and a cylindrical shaft at an opposite end andmachining a distal end portion of the cylindrical shaft on opposingsides thereof to form the shaft portion from the cylindrical shaft andto generate two opposing flats. The formation of the flats may realizethe blade portion as a planar shaft extension or end portion having atleast one edge surface that is a cylindrical section continuous andcoaxial with a cylindrical outer surface of the shaft portion.

The machining of the distal end portion of the cylindrical shaftpreferably includes rotating a cutting tool about a rotation axisextending parallel to at least one of the flats.

The machining of the distal end portion of the cylindrical shafttypically includes forming an end surface of the shaft portion as acylindrical section having an axis parallel to the rotation axis and oneor both flats.

The present invention provides an ultrasonic instrument, particularly anablation or bone-cutting instrument that is more easily manufactured andthat can have tighter or more consistent specifications. Thus qualitycontrol is facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an ultrasonic surgical instrument orprobe pursuant to the present invention.

FIG. 2 is an isometric view, on a larger scale, of a distal end portionof the instrument or probe of FIG. 1.

FIG. 3 is a side elevational view of the distal end portion of FIG. 2.

FIG. 4 is a top plan view of the distal end portion of FIGS. 2 and 3.

FIG. 5 is a bottom plan view of the distal end portion of FIGS. 2-4.

FIG. 6 is a longitudinal cross-sectional view of a tubular tool blankschematically illustrating two envelopes of cutting tool paths on anupper side and a lower side, in a method for manufacturing theinstrument or probe of FIGS. 1-5, in accordance with the presentinvention.

FIG. 7 is an isometric view of a distal end portion of anotherultrasonic surgical instrument or probe pursuant to the presentinvention.

FIG. 8 is a side elevational of the distal end portion of FIG. 7.

FIG. 9 is an isometric view of a distal end portion of a furtherultrasonic surgical instrument or probe pursuant to the presentinvention.

FIG. 10 is a side elevational of the distal end portion of FIG. 9.

FIG. 11 is an isometric view of a distal end portion of an additionalultrasonic surgical instrument or probe pursuant to the presentinvention.

FIG. 12 is a side elevational of the distal end portion of FIG. 11.

FIG. 13 is an isometric view of a distal end portion of yet anotherultrasonic surgical instrument or probe pursuant to the presentinvention.

FIG. 14 is a side elevational of the distal end portion of FIG. 13.

FIG. 15 is an isometric view of a distal end portion of yet a furtherultrasonic surgical instrument or probe pursuant to the presentinvention.

FIG. 16 is a side elevational of the distal end portion of FIG. 15.

DETAILED DESCRIPTION

Each of the ultrasonic surgical instrument embodiments illustrated inthe drawings comprises a cylindrical shaft and a blade at a distal offree end of the shaft, the blade being unitary and continuous with theshaft, without an intervening joint. The manufacture of theseinstruments entails machining a distal end of a tool blank andparticularly a distal end portion of a tubular shaft thereof.

As depicted in FIG. 1, a surgical instrument 20 comprises a cylindricalshaft 22 and a blade 24 at a distal or free end of the shaft, the bladebeing unitary and continuous with the shaft, without an interveningjoint. Instrument 20 (and all of the instruments disclosed herein)typically further comprises a radially or transversely enlarged proximalend portion 26 at a proximal end of the shaft 22 opposite blade 24.Proximal end portion 26 is configured for attachment to anelectromechanical transducer device (not shown) such as a piezo-electricstack housed inside an instrument hand piece (not shown).

Shaft 22 has a longitudinal axis 28 and blade 24 includes a flat orplanar blade body 30 with a proximal end 32 eccentrically disposedrelative to shaft axis 28. Thus, blade body 30 or at least a proximalend portion thereof is disposed eccentrically relative to shaft 28.

In each embodiment of an ultrasonic surgical instrument disclosedherein, a blade includes a flat or planar blade body with a proximal endeccentrically disposed relative to a shaft axis. Thus, the blade body orat least a proximal end portion thereof is disposed eccentricallyrelative to the instrument shaft.

As illustrated In FIGS. 2-4, blade body 30 has at least one edge orperipheral surface 34 that is an endless cylindrical section orperimetral surface continuous and coaxial with a cylindrical outersurface 36 of shaft 22.

Each embodiment of an ultrasonic surgical instrument disclosed hereinhas a blade body with at least one edge or peripheral surface in theform of a cylindrical section continuous and coaxial with a cylindricalouter surface of the instrument shaft.

As illustrated in FIG. 6, a method for manufacturing surgical instrument20 comprises providing a tool blank 38 including an enlarged connectorportion 26 (FIG. 1) at one end and a cylindrical shaft 40 at an oppositeend and machining a distal end portion 42 of the cylindrical shaft onopposing sides (not designated) thereof to form the shaft portion 22(FIG. 1) of instrument 20 from cylindrical shaft 40 of the blank 38 andto generate two opposing flats or major blade surfaces 44 and 46. Theformation of flats 44 and 46 realizes the blade portion 24 (FIGS. 1-5)as a planar shaft extension or end portion having edge or peripheralsurface 34.

As illustrated in FIG. 3, blade body 30 extends at an angle a1 withrespect to shaft axis 28 and intersects the shaft axis. Blade body 30 isa planar shaft extension machined down from an end portion of acylindrical blank so that the blade body extends only within acylindrical envelope, inclusive of the cylindrical envelope, that iscoaxial and co-cylindrical with the cylindrical outer surface 36 ofshaft 22. Blade body 30 extends across a first cylinder that isco-cylindrical with the inner surface of shaft 22 defining bore orchannel 50. A distal terminal portion (not designated) of blade body 30is located entirely between (and inclusive of) that inner firstcylinder, co-cylindrical with bore or channel 50, and the cylindricalenvelope (an outer second cylinder) that is co-cylindrical with outersurface 36 of shaft 22, the terminal portion being continuous withoutbreak or interruption. Shaft 22 has an end face 48 contiguous with theproximal end 32 of blade body 30 and additionally has a channel or bore50 with an outlet 52 in the end face 48. Flats 44 and 46 are a planarfirst major lateral surface and a planar second major lateral surfacefacing oppositely to one another.

It is to be noted that a rotating cutting tool (schematically depictedat 49) is used to cut flats 44 and 46 from distal end portion 42 (FIG.6) of blank 38. The rotating cutting tool has a circular or cylindricalcutting face (not separately designated) that is moved along a firstlinear path 51 (FIG. 6) so as to exhibit an oblate oval cutting envelope54, as shown in FIG. 6. Shaft end face 48 is formed simultaneously withthe formation of a proximal end portion of flat 44 by the same cuttingaction and accordingly takes the form of a cylindrical section. Ofcourse, end face 48 may be separately and additionally machined in asupplemental process to provide the end face with a planar form.

The same rotating cutting tool 49 may be used to form lower flat 46, asschematically indicated by another oblate oval cutting envelope 56, asshown in FIG. 6.

As depicted in FIGS. 2 and 4, blade 24 is provided in flat or majorlateral surface 44 with a groove 150 continuous with a channel or bore50 at outlet 52. Blade 24 is further formed so as to exhibit a throughhole 152 at an end of groove 150 opposite end face 48 and outlet 52.Groove 150 extends from outlet 52 to through hole 152. As shown in FIG.5, flat or major lateral surface 46 is formed with an additional groove154 communicating with through hole 152. Groove 154, continuous andcommunicating with through hole 152, is disposed on a side of thethrough hole opposite outlet 52 and the distal or free end of shaft 22.Groove 154 has a distal end (not designated) spaced from a distal tip(not designated) of blade body 30, the distal tip being closed andcontinuous, without break or interruption. Groove 154 is tapered from awide end at through hole 152 and a closed narrow end 156 at flat ormajor lateral surface 46. Surface 46 is in the form of an annular ovalsurface with an oval center edge 158 formed by through hole 152 andgroove 154.

In each of the embodiments of FIGS. 7-16, a blade extends parallel to anaxis of an elongate linear instrument shaft and to one side of thataxis. Accordingly, each blade body necessarily has a proximal end thatis unitary with the distal end of the shaft at a point that iseccentrically disposed relative to the shaft, i.e., at a distance fromthe shaft axis. The various blades are produced by machining a blank inthe form of a tubular rod with a cutting tool having a circular cuttingedge or cylindrical cutting surface, with that cutting tool being movedalong a path parallel to the shaft axis. The distal end faces of theshafts may have a cylindrically concave surface produced by the circularor cylindrical cutting tool or may be flat as illustrated, which shapeis rendered by further machining, for instance, by moving the circularor cylindrical cutting surface along a linear path at an angle from theshaft axis.

As depicted in FIGS. 7 and 8, a surgical instrument 60 comprises acylindrical shaft 62 and a blade 64 at a distal or free end of theshaft, the blade being unitary and continuous with the shaft, without anintervening joint. Instrument 60 further comprises a radially ortransversely enlarged proximal end portion 26 (FIG. 1) at a proximal endof the shaft 62 opposite blade 64 or connecting to an electromechanicaltransducer device (not shown) such as a piezo-electric stack housedinside an instrument hand piece (not shown).

Blade 64 has a planar upper major surface 66 facing an axis 68 ofinstrument shaft 62 and a planar lower major surface 70 facing in theopposite direction, away from axis 68. Surfaces 66 and 70 are parallelto one another and to axis 68. Blade 64 is spaced at such a distancefrom axis 68 that no groove is formed in upper surface 66. A channel orlumen 72 of shaft 62 has an outlet port 74 over a proximal end ofsurface 66 so that irrigant flowing under pressure through the channelor lumen empties out onto surface 66. Blade 64 has a distal end face 76that is flat and oriented perpendicularly to shaft axis 68. Blade 64 hasa pair of lateral peripheral edge surfaces 78 that are cylindricalsections continuous and coaxial with an outer surface (not separatelydesignated) of shaft 62.

As illustrated in FIGS. 9 and 10, a surgical instrument 80 comprises acylindrical shaft 82 and a blade 84 at a distal or free end of theshaft, the blade being unitary and continuous with the shaft, without anintervening joint. Instrument 80 further comprises a radially ortransversely enlarged proximal end portion 26 (FIG. 1) at a proximal endof the shaft 82 opposite blade 84 or connecting to an electromechanicaltransducer device (not shown) such as a piezo-electric stack housedinside an instrument hand piece (not shown).

Blade 84 has a planar upper major surface 86 facing an axis 88 ofinstrument shaft 82 and a planar lower major surface 90 facing in theopposite direction, away from axis 88. Surfaces 86 and 90 are parallelto one another and to axis 88. Blade 84 is spaced at such a distancefrom axis 68 that an elongate groove 91 is formed in upper surface 86.Groove 91 is continuous and coaxial with a cylindrical surface (notseparately designated) of a channel or lumen 92 of shaft 82 andcommunicates with the channel or lumen via an outlet port 94 thereof.During use of the instrument 80, irrigant flows under pressure throughchannel or lumen 92 and empties into groove 91, from which the irrigantis distributed over surface 86. Blade 84 has a beveled distal end face96 that is flat with a straight terminal edge 93 and rounded corners 95and oriented at an angle to shaft axis 88. Groove 91 terminates in or atbeveled distal end face 96. Blade 84 has a pair of lateral peripheraledge surfaces 98 that are cylindrical sections continuous and coaxialwith an outer surface (not separately designated) of shaft 82.

FIGS. 11 and 12 depict a surgical instrument 100 that is identical toinstrument 80 except for the provision of a through slot 102 in blade84. Reference numbers in FIGS. 11 and 12 are the same as thosedesignating like features or elements of surgical instrument 80. Slot102 is formed in groove 91, essentially midway along the length thereof,and divides the groove into a proximal groove segment 104 and a distalgroove segment 106. Slot 102 facilitates the flow of irrigant fromgroove 91 or groove segment 104 to under surface 90.

As shown in FIGS. 13 and 14, a surgical instrument 110 comprises acylindrical shaft 112 and a blade 114 at a distal or free end of theshaft, the blade being unitary and continuous with the shaft, without anintervening joint. Instrument 110 further comprises a radially ortransversely enlarged proximal end portion 26 (FIG. 1) at a proximal endof the shaft 112 opposite blade 114 or connecting to anelectromechanical transducer device (not shown) such as a piezo-electricstack housed inside an instrument hand piece (not shown).

Blade 114 has a planar upper major surface 116 facing an axis 118 ofinstrument shaft 112 and a planar lower major surface 120 facing in theopposite direction, away from axis 118. Surfaces 116 and 120 areparallel to one another and to axis 118. Blade 114 is spaced at such adistance from axis 118 that a short groove section 121 is formed inupper surface 116, where the groove section is continuous and coaxialwith a cylindrical surface (not separately designated) of a channel orlumen 122 of shaft 112 and communicates with the channel or lumen via anoutlet port 124 thereof. Blade 114 is also provided with an elongatethrough slot 126 extending parallel to shaft axis 118. At a distal endof through slot 126, blade 114 has a distal groove section 128 thatextends from slot 126 on one side to a circular edge or cylindrical endsurface 130 on an opposite side. Blade 114 has a pair of lateralperipheral edge surfaces 132 that are cylindrical sections continuousand coaxial with an outer surface (not separately designated) of shaft112.

During use of the instrument 110, irrigant flows under pressure throughchannel or lumen 122 and into proximal groove section 121 and then intoslot 126 from which the irrigant may exit onto both major blade surfaces116 and 120 and to circular edge or cylindrical end surface 130.

FIGS. 15 and 16 depict a surgical instrument 140 that is identical toinstrument 110 except for a beveling at the distal end of theinstrument. Reference numbers in FIGS. 15 and 16 are the same as thosedesignating like features or elements of surgical instrument 110 inFIGS. 13 and 14. Instrument 140 has a beveled end surface 142. Distalgroove section 128 is truncated by the formation of beveled end surface142 and exhibits a tapering which facilitates distribution of irrigantfrom slot 126 over beveled end surface 142.

It is evident that in each of the instrument embodiments disclosedherein, the instrument shaft 22, 62, 82, 112 has an end face 48, 144,146, 148 contiguous with a proximal end of the blade 25, 64, 84, 114 andalso has a channel or bore 50, 72, 92, 122 with an outlet 52, 74, 94,114 in that end face. The blade 25, 64, 84, 114 may be provided in amajor lateral surface or flat 44, 86, 116 with a groove 91, 104, 121continuous with the channel or bore 50, 92, 122 at the outlet 52, 94,114 thereof. The groove 91 may extend the length of the blade to adistal end of the blade. Alternatively, where the blade 24, 84, 114 isprovided with a through slot or hole 102, 126, the groove includes asection 104, 121 extending from the outlet 94, 124 of the shaft channelor bore 92, 112 to a proximal side of the through slot or hole 102, 126.The blade 84, 140 may be provided at a distal end, opposite the shaft82, 112, with a beveled surface 96, 142 inclined with respect to theaxis 88, 143 (FIG. 16). Alternatively or additionally, the blade 24, 114may be formed with an arcuate distal tip, where the distal tip has acircular or cylindrical surface with an axis oriented perpendicular tothe shaft axis.

As discussed hereinabove with reference to FIG. 6, a method formanufacturing a unitary ultrasonic surgical instrument having a shaftportion 22, 62, 82, 112 and a blade portion 24, 64, 84, 114 at a distalof free end of the shaft comprises providing a tool blank 38 includingan enlarged connector portion 26 at one end and a cylindrical shaft 40at an opposite end and machining a distal end portion 42 of thecylindrical shaft on opposing sides thereof to form the shaft portion22, 62, 82, 112 from the cylindrical shaft and to generate two opposingflats 44, 66, 86, 116 and 46, 70, 90, 120. The formation of the flats44, 66, 86, 116 and 46, 70, 90, 120 realizes the blade portion 24, 64,84, 114 as a planar shaft extension or end portion that may have atleast one edge surface 34, 78, 98, 132 that is a cylindrical sectioncontinuous and coaxial with a cylindrical outer surface of the shaftportion 22, 62, 82, 112. The machining of the distal end portion 42 ofthe cylindrical shaft 40 of the tool blank 38 typically includesrotating cutting tool 49 about a rotation axis extending parallel to atleast one of the flats 44, 66, 86, 116 (perpendicular to the plane ofthe drawing in FIG. 6). Distal end portion 42 of the cylindrical shaft40 of the tool blank 38 may be further machined along edge surfaces 34,78, 98, 132, for instance, to taper the blade portion 24, 64, 84, 114,that is to reduce the free-end width thereof.

The machining of the distal end portion 42 of the cylindrical shaft 40typically includes forming an end surface 48, 144, 146, 148 of the shaftportion 22, 62, 82, 112 as a cylindrical section (not shown) having anaxis parallel to the rotation axis of the tool 49 and one or both flats44, 66, 86, 116 and 46, 70, 90, 120. Further machining, either with tool49 or a different tool can be undertaken to form shaft end surfaces 48,144, 146, 148 as flat or planer surfaces inclined with respect to shaftaxes 28, 68, 88, 118.

Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theclaimed invention. Accordingly, it is to be understood that the drawingsand descriptions herein are proffered by way of example to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

What is claimed is:
 1. An ultrasonic surgical instrument comprising acylindrical shaft having a longitudinal axis and a blade at a distal orfree end of said shaft, said blade being unitary and continuous withsaid shaft, without an intervening joint, said blade including a flat orplanar blade body extending at an angle with respect to said axis, saidblade body having at least one edge surface that is a cylindricalsection continuous and coaxial with a cylindrical outer surface of saidshaft, wherein: said shaft has an end face contiguous with a proximalend of said blade body, said shaft having a channel or bore with anoutlet in said end face; and said blade body has a major lateral surfacefacing said axis, said blade body being provided in said major lateralsurface with a tapered longitudinal groove having a depth andcross-sectional area each varying with distance along said groove. 2.The surgical instrument defined in claim 1 wherein said blade body isprovided with a through slot or hole communicating and continuous withsaid groove.
 3. The surgical instrument defined in claim 1 wherein saidblade body is provided with an arcuate distal tip.
 4. The surgicalinstrument defined in claim 1 wherein said blade body intersects saidaxis.
 5. The surgical instrument defined in claim 1 wherein said bladebody has a through hole communicating with said channel or bore via saidoutlet.
 6. An ultrasonic surgical instrument comprising a cylindricalshaft having a longitudinal axis and a blade at a distal or free end ofsaid shaft, said blade being unitary and continuous with said shaft,without an intervening joint, said blade including a flat or planarblade body extending at an angle with respect to said axis, said bladebody having at least one edge surface that is a cylindrical sectioncontinuous and coaxial with a cylindrical outer surface of said shaft,wherein: said blade body intersects said axis; and said shaft has an endface contiguous with a proximal end of said blade body, said shafthaving a channel or bore with an outlet in said end face, said bladebody having a planar first major lateral surface and a planar secondmajor lateral surface facing oppositely to one another, said blade bodybeing provided in said first major lateral surface with a longitudinalgroove, said blade body being further provided with a through hole at anend of said groove.
 7. The surgical instrument defined in claim 6wherein said second major lateral surface is formed with an additionalgroove communicating with said through hole.
 8. The surgical instrumentdefined in claim 7 wherein said additional groove is tapered from a wideend at said through hole and a closed narrow end at said second majorlateral surface.
 9. An ultrasonic surgical instrument comprising: acylindrical shaft having a longitudinal axis and an end face at a distalor free end of said shaft; and a blade contiguous with said distal orfree end of said shaft at said distal end face, said blade being unitaryand continuous with said shaft, without an intervening joint, said bladeincluding a flat or planar blade body extending at an angle with respectto said axis, said blade body having at least one edge surface that is acylindrical section continuous and coaxial with a cylindrical outersurface of said shaft, said shaft having a channel or bore with anoutlet in said end face, said blade body having a pair of major lateralsurfaces and being provided with a through hole extending between saidmajor lateral surfaces, said blade body being provided in one of saidmajor lateral surfaces with a groove continuous with and communicatingwith said through hole and disposed on a side of said through holeopposite said outlet and said distal or free end of said shaft, saidgroove having a distal end spaced from a distal tip of said blade body,said distal tip being closed and continuous, without break orinterruption.